1. Field of the Invention
This invention is directed to the technology of transfer of solid particulate materials. It more particularly relates to means for transferring particulate matter from a container while minimizing the emission of dust to the surrounding atmosphere.
2. Description of Related Art
In industry, it is common to require the transfer of particulate material, especially powdered material, from drums or other suitable shipping containers, into an operating system designed to make use of the particulate material. In the past, this was accomplished by simply turning the drum over and thereby emptying its contents into a suitable hopper or the like. 0f course this caused the escape of substantial quantities of the contained particulate material as a dust which contaminated the surrounding atmosphere and was at least potentially injurious to the health of the workers in the vicinity.
In more recent times, it was, and still is, also known to transfer the particulate contents of a shipping container by simply removing the lid thereof, and vacuuming out the contents directly into the operating system being fed. This is inherently a cleaner operation than simply just pouring the drum contents into an open hopper.
In the prior process of vacuuming out the contents of the shipping drums, it was and is necessary for the drum lid to be off so that the worker who is doing the vacuuming can see into the drum to insure that all of the particulate contents thereof has been sucked out, even of the lower corners of the drum. Additionally, for a vacuum system to work, there must be means to let air into the drum to fluidize the particulate contents thereof and allow the thus fluidized particles to be lifted out of the container. Therefore vacuuming cannot be done in a sealed system, or even with a closed drum lid.
In addition to the presentation of a clean-up problem, this type of operation also presents a serious health problem to the workers charged with the responsibility of emptying the drums. Further, the dust is also liable to get into machinery and cause all sorts of maintenance problems.
In the past, this problem has sometimes been attacked by carrying out the transfer in a sealed room, a so-called "dust room", or by using the services of a large hood with special ventilation facilities. Personnel who operate such a facility need to wear protective clothing and to utilize breathing apparatus in order to minimize their contamination from constant, or even intermittent, contact with the dust. Obviously, this makes for a difficult and costly operation.